Vertical type paper machine

ABSTRACT

A pair of rolls are disposed in vertically spaced relation to each other within a paper producing enclosure and a wire cloth is put on the rolls to form an endless wire cloth loop. For forming paper on one surface of the wire cloth by supplying a paper material, i.e., paper slurry, to the one surface, a paper layer forming chamber which is substantially in an air tight state is provided and maintained at an air pressure higher than atmospheric pressure so that air passes through the wire cloth thus constantly forces the paper layer formed on the wire cloth surface toward the wire cloth to thereby prevent the paper layer from falling off from the wire cloth surface and to remove excess paper material adhering to the wire cloth surface, while sufficiently dehydrating the material. Thus a paper layer having uniform thickness is produced at a high rate.

United States Patent [191 Uchiyama 5] Dec. 10, 1974 [73] Assignee: Maruishi llron Works Co., Ltd.,

Shizuoka, Japan [22] Filed: June 4, 1973 [21] Appl. No.: 366,860

3,650,892 3/1972 Genz et a] 1. 162/348 X Primary ExaminerS. Leon Bashore Assistant ExaminerRichard V. Fisher Attorney, Agent, or FirmKurt Kelman [57] ABSTRACT A pair of rolls are disposed in vertically spaced relation to each other within a paper producing enclosure and a wire cloth is put on the rolls to form an endless wire cloth loop. For forming paper on one surface of the wire cloth by supplying a paper material, i.e., paper slurry, to the one surface, a paper layer forming chamber which is substantially in an air tight state is provided and maintained at an air pressure higher than atmospheric pressure so that air passes through the wire cloth thus constantly forces the paper layer formed on the wire cloth surface toward the wire cloth to thereby prevent the paper layer from falling off from the wire cloth surface and] to remove excess paper material adhering to the wire cloth surface, while sufficiently dehydrating the material. Thus a paper layer having uniform thickness is produced at a high rate.

1 Claim, 2 Drawing Figures PATENTEL SE8 1 DISH sum 1 or 2' VERTICAL TYPE PAPER MACHINE BACKGROUND OF THE INVENTION The present invention relates to a vertical type paper machine.

It has been known that the conventional paper machine using a circular wire cloth has inherent disadvantages in that: because the wire cloth portion thereof on which the paper layer is formed comprises a circular wire cloth, the paper layer formed on one surface of the wire cloth tends to come off due to the centrifugal force produced by the rotation of the wire cloth; the flow of paper material in the filtering enclosure is disturbed by the rotation of the wire cloth to thereby make the disposition of the paper material on the wire cloth surface ununiform; and dehydration of the paper layer disposed on the wire cloth surface cannot be effected satisfactorily. These disadvantages are aggravated when the rotational speed of the wire cloth is increased to increase the paper producing rate.

A primary object of the present invention is to provide a paper machine which is inherently free of the disadvantages of the conventional paper machine and which can produce a uniform paper layer at a higher rate than attained by the conventional paper machine.

Another object of the present invention is to provide a paper machine which can produce paper sheet at a high rate while effecting sufficient dehydration thereof.

SUMMARY OF THE INVENTION pressure higher than atmospheric pressure during the formation of the paper layer. As the compressed air in the paper layer forming chamber passes through the wire cloth to be exhausted to the outside, so that the paper layer does not come off the wire cloth surface even when the wire cloth loop is run at high speed. Thus an efficiently dehydrated paper layer of uniform thickness is obtained.

The' above and other objects and features of the present invention will become apparent by reading the following detailed explanation of an embodiment of the present invention with reference to the attached drawings.

BRIEF EXPLANATION OF THE DRAWING FIG. I is a vertical cross section of an embodiment of a vertical type paper machine according to the present invention; and

FIG. 2 is an enlarged perspective view of the main portion of the paper machine shown in FIG. 1.

DETAILED EXPLANATION OF THE INVENTION Referring now to FIG. l, a pair of vertically spaced rolls 2 and 2' are provided in a filtering enclosure 1 having at the vicinity of its bottom a drain port 6 for discharging white water contained in the paper material. An endless wire cloth 3 is supported and driven by the pair of rolls 2 and 2'. The wire cloth loop 3 is maintained under constant tension by a strech roll 20 disposed intermediately between the rolls 2 and 2. In a lower portion of the enclosure 1, a paper slurry supply tube 9, which houses a roll 10, is provided for uniformly feeding paper slurry to the outer surface of the wire cloth 3. One end of the tube 9 is connected through a pump 16 disposed in an extension of the enclosure 1 to a paper slurry supply tank (not shown). The other end of the tube 9 opens onto the outer surface of the wire cloth 3 between the rolls 2 and 2'. Inside of the wire cloth loop 3, a filter portion 4 and a save-all vessel 7 are provided at a position opposing the open end of the supply tube 9. White water passed through the wire cloth 3 passes through the filter portion 4 to the save-all vessel 7. The vessel 7 has an opening 8 in the lower portion of the side walls thereof. Accordingly, the white water in the save-all vessel passes through the opening 8 to the lower portion of the filtering enclosure 1 and then is fed, together with the white water present at that time in the enclosure 1, through the drain port 6 to the pump 16. The portion of the white water supplied through the supply tube 9 to the wire cloth 3 which overflows enters a paper material overflow tank 11 defined by the outer surface of the supply tube 9 and the inner walls of the enclosure I and recirculated through a drain opening 12 and then through the drain port 6 to the pump 16. A paper layer forming chamber 13 is defined above the paper slurry overflow tank 11 by the side plates of the enclosure 1, cover plate 14 of the same and the wire cloth 3. Generally U-shaped sealing bands 21 are secured to the opposite side plates of the enclosure 1 and extend along the opposite side edges of the wire cloth 3 so that the side edges of the wire cloth 3 cover the upper open ends of the sealing bands 21. Pump l6,causes white water to flow along the grooves of the sealing bands thus to seal the side edges of the wire cloth to prevent the paper slurry from leaking into the interior of the loop and also for maintaining the interior of the paper layer forming chamber substantially air tight.

The upper end of the chamber is provided with a blower port 15 through which compressed air is blown into the chamber 13 to maintain the pressure therein at higher than atmospheric pressure. A felt blanket 17 runs tangentially to the upper outer periphery of the roll 2, in smooth contact therewith. A pressure roll 18 is provided in pressure contact relation to the periphery of the roll 2 and thus the paper layer 19 on the wire cloth 3 is transferred from the wire cloth surface to the lower surface of the felt blanket 17 due to the compression force exerted between the rolls 2 and 18.

Since the paper machine according to the present in vention is constructed as above described, the paper slurry 5 fed through the supply tube 9 by the pump 16 is supplied to the wire cloth 3 after the flow thereof is regulated by the flow regulating roll 10 and deposited on the outer surface of the wire cloth 3 and then lifted with the upward movement of the wire cloth 3 due to the rotation of the rolls 2 and 2'. The paper layer forming chamber 13 is maintained at higher than atmospheric pressure by compressed air blown continuously out from the blower opening 15 and discharged through the wire cloth 3 and the filter portion 4 to the atmosphere. Accordingly, the paper layer formed on the outer surface of the wire cloth 3 is continuously held on the outer surface of the wire cloth without danger of falling while excess paper slurry on the wire cloth is removed. The white water contained in the paper slurry is filtered out by the wire cloth 3 and the filter portion 4 or by the compression between the rolls 2 and 18 and thus a paper layer of uniform thickness is formed on the wire cloth surface. It is not always necessary to direct the compressed air blown from the blowing opening 15 onto the paper layer disposed on the wire cloth surface as above mentioned and it is only necessary to maintain a fixed or constant air pressure within the paper layer forming chamber 13. Therefore, any shape of blower opening maybe employed and, for example, it is possible to maintain the pressure in the paper layer forming chamber at 20 to 150 mm Aq by employing an air fan to supply compressed air into the paper layer forming chamber and by regulating the amount of air supply by means of a damper for pressure regulation. The paper formed on the wire cloth is transferred to the top portion of the upper roll 2 and when thepaper layer passes between the compression roll 18 and the upper roll 2 it is further compressed and dehydrated resulting in the adhesion thereof to the lower surface of the blanket 17 which transfers it to the next processing station.

The white water contained in the paper slurry and now passed through the wire cloth 3 is collected in a white water vessel 7 and fed through the discharge opening 8 to the drain opening 6. The portion of the paper slurry which overflows at the open end of the paper slurry supply tube 9 is collected temporarily in a paper slurry overflow tank 11 and then fed to the drain opening 6. At the drain opening, it is united with the white water from the white water vessel and fed to the pump 16. Then the confluence is further united with fresh paper slurry at the pump and fed to the supply tube 9. In order to maintain the pressure in the paper layer forming chamber, i.e., to keep the chamber at a constant pressure, the water head of the paper slurry in the tank should be maintained at a position above the drain opening 12.

As will be apparent from the foregoing detailed explanation, since thepaper machine according to the present invention utilizes a pair of vertically spaced rolls in the enclosure and an endless loop of wire cloth supported and driven by the rolls, on the outer surface of which the paper slurry is deposited, and since the paper layer forming chamber of the machine is maintained at a constant pressure, the paper layer deposited on the wire cloth surface is always forced onto the surface so that it will not be caused to separate therefrom by centrifugal force even when the rolls are driven at high speed. Furthermore, since excessive paper slurry on the wire cloth surface is removed therefrom and sufficient dehydration thereof is effected, a paper sheet having uniform thickness and a smooth surface is produced at a high rate. The paper slurry can be supplied to the wire cloth surface uniformly without any turbu lence of the flow thereof because it is supplied to the wire cloth surface in such a manner that there is no inversal effect of the moving direction of the wire cloth against the slurry supply. In addition to the above mentioned effects obtainable by the present paper machine, since it employs a verticalarrangement of the wire cloth, the installation area of the present machine becomes smaller than that of the conventional machine and a larger number of machines or a larger machine can be installed in the same area.

I claim:

1. A vertical type papermaking machine comprising in combination, a pair of rolls rotatably disposed axially parallel and one vertically above the other, a wire cloth supported under tension about said rolls, a portion of said wire cloth being disposed vertically for movement from the lower roll upwardly to the upper roll, a paper layer forming chamber defined by said vertically disposed wire cloth portion and surrounding enclosing walls, said paper layer forming chamber being continuously maintained at higher than atmospheric pressure by compressed air supplied thereto,said surrounding enclosing walls being substantially air-tight by sealing means disposed along edges of said wire cloth, means for supplying paper slurry onto a lower portion of the vertically disposed portion of wire cloth, said paper slurry forming a paper layer by means of higher than atmospheric air in the paper layer forming chamber passing through the vertically disposed wire cloth above said lower portion, and means for removing the paper layer from the wire cloth at said upper roll. 

1. A vertical type papermaking machine comprising in combination, a pair of rolls rotatably disposed axially parallel and one vertically above the other, a wire cloth supported under tension about said rolls, a portion of said wire cloth being disposed vertically for movement from the lower roll upwardly to the upper roll, a paper layer forming chamber defined by said vertically disposed wire cloth portion and surrounding enclosing walls, said paper layer forming chamber being continuously maintained at higher than atmospheric pressure by compressed air supplied thereto, said surrounding enclosing walls being substantially air-tight by sealing means disposed along edges of said wire cloth, means for supplying paper slurry onto a lower portion of the vertically disposed portion of wire cloth, said paper slurry forming a paper layer by means of higher than atmospheric air in the paper layer forming chamber passing through the vertically disposed wire cloth above said lower portion, and means for removing the paper layer from the wire cloth at said upper roll. 